Net Hydrodynamic Load Model

1. Description

The net load model is used for modelling nets, such as fish cage net panels. A complete net is normally modelled as a set of segments where each segment represents a net panel, specified by a cable/bar cross section with equivalent properties.

Drag and lift coefficients are derived automatically from the net solidity ratio (SN), and the specified added mass coefficients and net width are scaled along the element length by linear interpolation between the values at segment end 1 and end 2.

Net load may only be used with bar elements (no bending or torsional stiffness).
The net plane must be defined via the Local Element Axis input. The net plane is the plane containing the updated local element X-axis and the fixed reference vector.
If the specified external area (AE) is zero, neither hydrostatic nor hydrodynamic loads will act on the cross section.

The drag and lift coefficient equations are valid for a solidity ratio range of [0.13, 0.32].

2. Theory

For details, see Theory - Load models - Net loads.